The present invention relates to a digital camera and, particularly, to a digital camera capable of obtaining a wide view still image from a series or sequence of images shot by operating a digital camera by panning or a combination of panning and other camera movements.
In recent years, a variety of kinds of digital cameras have been placed on the market as tools for collecting information. Technically, various cameras have been made that address the importance of portability and functions related to the quality of the picture obtained by using the camera. The images shot are digital, and hence can be readily input to a computer, transmitted, placed on a home page of the Internet, and printed. Therefore, use of digital cameras is rapidly spreading.
At present, however, the picture quality of digital cameras is quite inferior to that of traditional silver salt, photographic film cameras. The average resolution of the current digital cameras is 320 pixelsxc3x97240 pixels, which makes it difficult to grasp the content of the image when a large angular field of view is used. This leads to limitations in various fields of use of such cameras.
In the field of business presentations, when a whiteboard of an average size is used for a meeting or the like and is shot by using a digital camera, it is at times difficult to read the written contents on the whiteboard, when it is attempted to capture the entire whiteboard in a single image due to insufficient resolution. When a slender advertisement board or a wide building is to be shot with a digital camera with the expectation of capturing details in the resultant picture, furthermore, many pictures must be taken from different points of view in order to obtain satisfactory resolution.
Similarly, whenever a user wants to shoot a picture of a scene to obtain a high-definition, wide view image, as when a commemorative picture is taken of many people together, a plurality of pictures must be shot in a divided manner to capture the entire scene. The same holds true for a user who wants to take a panoramic picture of mountains, for example. What the user really wants to see in the final image is detail in the picture. In practice, however, the user must obtain a plurality of views of the scene from several images, and synthesize a single wide view image in his mind from these views.
In the field of computer graphics, one product addressing this issue is QuickTime VR of Apple Co., which provides a single panoramic still image covering a surrounding scene of 360 degrees. To obtain a panoramic still image using this product, it is necessary to form a dynamic image starting at an arbitrary visual point and then take many shots to cover the whole surrounding scene. Then, a user must carefully paste the images together by using an image editing tool. Accordingly, editing of the shots is required to obtain the panoramic image.
In comparison to the present invention, there has been proposed an xe2x80x9cImage Sensing Device, Image Processing Device and Image Reproducing Devicexe2x80x9d, disclosed in Japanese Patent Laid-Open No. 121226/1994 (hereinafter referred to the prior art method). In order to obtain a wide view still image from a series of images, by using the prior art method, an operation is executed to detect, with respect to a preceding image, a novel image portion in a succeeding image for a plurality of succeeding images. Then, the preceding image and the novel image portions obtained from the succeeding images are joined together to form a wide image. The joining together of the images is performed automatically, but not in real time.
That is, in the prior art method, the moving vectors of the image are obtained and are referred to in order to set an image portion that is to be joined. However, since the moving vectors of the image are obtained in the prior art method, a wide view still image cannot be obtained in real time. Specifically, the prior art method uses pattern matching that is accomplished using two-dimensional template matching by dividing each frame (the preceding and succeeding images) into a plurality of blocks. In order to achieve real time processing for this type of pattern matching, it is necessary to have a special LSI for each of the blocks. Accordingly, this requires a large number of LSIs for real time processing. This is expensive and impractical. That is, the image sensing device becomes expensive and large when it is intended to obtain a wide view image in real time. To realize a small and cheap image sensing device that provides wide view images, on the other hand, it becomes necessary to operate a plurality of templates for matching using a small number of LSIs, which has been difficult in the prior art, so real-time processing in digital cameras has not been practical.
As described above, conventional digital cameras are convenient to use from the standpoint of the functions provided, but are inferior to silver salt based photographic film cameras from the standpoint of picture quality. Therefore, in order for users to obtain a wide view image many pictures of a scene must be taken in a divided manner and, in some cases, the user must paste the images together using an image editing tool on a computer.
A first object of the present invention is to provide a digital wide camera of a small size capable of forming, in real time, a wide view still image similar to the image of a wide angle view, from the viewpoint of the user, with a high resolution.
A second object of the present invention is to provide a digital wide camera capable of forming a wide view still image by operating and controlling the images to synthesize an image at high speeds, including in real time.
A third object of the present invention is to provide a digital wide camera which makes it possible to confirm the progress of forming the wide view still image while the picture is being taken.
Although the expressions wide view and digital wide camera are used in discussing the present invention, the meaning relates to not only a wide angle view, as obtained for example, from wide angle lenses in the prior art, which is equally possible to obtain with the digital wide camera of the present invention, but also to an image obtained by using the camera that represents a view, from the viewpoint of the user, that is wider than that normally obtained by a single image. Further, the wide view image is considered to be not only wider, but also wider and/or taller in view than that of a normal view, wherein the extent of the view that is captured by the camera relates to the coverage of the scene by the user that is obtained by panning the camera or otherwise moving the camera in any direction while the scene is being shot.